Reduction of grain by 80%.

a farmer has some grain, which he would like to have sold, but unfortunately there is very much moisture in the grain. there are actually 90% moisture in the grain and you will probably not call it corn any more , but there is a man who would like to buyit but he would only buy when the moisture percentage is down at 80%
it is about 100 kg grain (with moisture) and the question is now how much weight grain (with moisture) when it is down to 80% moisture when the man will buy?

Re: Help!!!!

Ok, so the grain has two components: the 'solid stuff' and the moisture. Moisture disappears during the drying process, but the mass of the solid stuff remains the same. You start out with of solid stuff. After the drying process you still have 10 kg of solid stuff, but now it's of the total mass. I'll leave it up to you do the last calculation step.